The cast of SBS’ To the Beautiful You were caught dying over an adorable child actress who joined the actors as a special cameo.

The making of video was released on September 27 on SM Entertainment’s Youtube channel, revealing the scene where the little sister of Hyun Jae (Kang Ha Neul) steals the heart of Jae Hee (f(x)’s Sulli) and Eun Gyul (Lee Hyun Woo).

Likewise, during the filming, the actors couldn’t hide their smiles over 7-year old Kim Yoo Bin, who is also known as Super Junior Choi Si Won’s daughter from the SBS drama, Oh! My Lady in 2010.

Kang Ha Neul said in between shoots, “She’s so cute. I honestly don’t think I can act today. I can’t stop smiling. She’s so adorable. I wish she was my sister.”